1. Field of the Invention
This invention relates in general to certain new and useful improvements in inflatable and deflatable mattresses and, more particularly, to inflatable and deflatable mattresses which have a cratered or non-level upper surface configuration on the upper or body supporting surface which thereby lends to improved body supporting comfort.
2. Brief Description of the Related Art
Inflatable mattresses of the type involved in the present invention are sometimes referred to as xe2x80x9ccamping mattressesxe2x80x9d or xe2x80x9cself-inflatingxe2x80x9d mattresses. The mattresses are sometimes referred to as xe2x80x9cpadsxe2x80x9d.
Generally, these mattress include an inner foam core in an outer fabric which may be disposed around or otherwise bonded to the inner foam core. Moreover, mattresses of this type are constructed with voids on the interior so as to allow an introduction of air when a valve on the mattress is opened. They also provide for a deflating by compressing the mattress, such as by rolling the mattress, to force the air out through the valve.
Mattresses of the aforesaid type are often referred to as self-inflating mattresses, as aforesaid, inasmuch as air will rush into the interior of the mattress if the valve is opened and the latter is unrolled. If the valve is then closed, the air remains in the mattress and the mattress is inflated. In like manner, upon compressing the mattress and opening the valve again, the air escapes and the mattress can be rolled or folded.
The initial self-inflating air mattress was disclosed in the Lea, et al Pat. No. 4,025,974, which had an inner foam core and an outer fabric cover surrounding that foam core. The mattress was effective, although it did not provide for a pillow construction in the mattress and, moreover, it contained a relatively flat upper body supporting surface.
The concept of shaping foam with a polygonal pattern, such as a hexagonal pattern, has also been taught in U.S. Pat. No. 5,688,538 to Barr, et al, and U.S. Pat. No. 5,534,208 to Barr, et al. Nevertheless, and heretofore, there has not been any body supporting mattress of the type in which the outer fabric cover is fully integrally bonded to the foam core and the foam core and fabric cover together form an upper surface shape having a non-level cratered surface configuration, that is, one with a raised portions and grooves therebetween.
It has been found in connection with the present invention that self-inflating mattresses of the aforesaid type often times can be relatively uncomfortable if they are not disposed on a perfectly flat surface. However, in camping conditions and the like, the surface upon which the mattress is disposed is rarely flat. As a result, any rocks, branches or the like which may be disposed beneath the bottom surface of and bearing against the bottom surface of the mattress will be felt by the user laying on the mattress. In addition, these mattresses only have an average depth or thickness of approximately a few inches when inflated. Thus, if the user should lie on this mattress in a position in which a portion of the body, such as an elbow, knee or the like, compresses the foam, the user will feel the hard surface of the ground which, again, may present an uncomfortable feeling.
There have been attempts in the past to provide an inflatable mattress having a dimpled upper surface, that is, an upper surface having an egg-crate type construction. This mattress construction relied primarily upon a foam core having this dimpled construction with a fabric cover disposed over the entire foam core. However, there was no attempt to seal the fabric cover to the foam core inasmuch there was no effective sealing means to obtain an integral bond throughout the entire dimpled surface area.
Efforts have been made to provide somewhat of an even body distribution on the surface of the mattress. However, it has been found that in most prior art devices, the foam will shift relative to the outer cover somewhat distorting the configuration of the mattress. In addition, it has also been found that a party attempting to recline on the mattress is not necessarily held in a fixed position on that mattress, since any turning movement of the party reclining on the mattress will tend to cause a shifting of the fabric with respect to the foam core. Not only is this uncomfortable, but it precludes a fixed retention of the reclining individual on the mattress.
There have been attempts in the past to use a partial bonding of a fabric cover to a foam core. These attempts also relied upon the so-called xe2x80x9cspot bondingxe2x80x9d and which was often referred to as xe2x80x9cdiamond bondingxe2x80x9d. In effect, the fabric was bonded to the foam core in selected areas. However, this construction proved to shorten the overall longevity of the mattress inasmuch as a body reclining on the mattress might tend to cause the fabric to shift with respect to the foam core in the event of movement of the reclining individual and this, in turn, caused the fabric to literally pull away from the foam core. In many cases, the fabric would actually tear thereby destroying the air impervious structure of the mattress.
It would be desirable to provide a self-inflating mattress of this type which had a non-level surface pattern and in which the foam core and the outer fabric cover also presented the same non-level surface pattern without any shifting movement therebetween.
In addition, there have been self-inflating mattresses of the aforesaid type which also have a pillow portion constructed into the mattress. One such mattress is more fully illustrated and described in U.S. Pat. No. 5,117,517, dated Jun. 2, 1992, to Ping-Hung Su, one of the applicants herein. It would also be desirable to provide a mattress of the aforesaid type having a non-level body supporting surface construction and also with a pillow constructed therein.
It is, therefore, one of the primary objects of the present invention to provide a self-inflating mattress which has a non-level upper surface construction and which is relatively comfortable to a user when the mattress is disposed on a ground surface.
It is another object of the present invention to provide a self-inflating mattress of the type stated which can be constructed with a polygonal surface pattern of grooves and raised portions on an upper surface thereof.
It is a further object of the present invention to provide a self-inflating mattress of the type stated which can be constructed with or without a pillow therein.
It is an additional object of the present invention to provide a self-inflating mattress of the type stated in which an outer fabric cover is disposed around a foam core and in which the cover is bonded to the foam core, such that the non-level upper surface pattern is integral throughout the entire mattress.
It is another salient object of the present invention to provide a self-inflating mattress of the type stated which can be constructed at a relatively low cost and which is highly efficient in use and operation.
It is yet an additional object of the present invention to provide a method of making a self-inflating mattress of the type stated having an inner core and an outer fabric and bonding the fabric to the core and simultaneously forming a non-level upper body supporting surface pattern thereon.
With the above and other objects in view, our invention resides in the novel features of form, construction, arrangement and combination of parts presently described and pointed out in the claims.
The present invention relates in general terms to an inflatable mattress and, preferably, a self-inflating mattress capable of being folded or rolled into a small compact unit and unfolded or unrolled to a relatively flat body supporting condition. In this case, the body supporting condition could be a relatively flat condition so that the mattress serves as a sleeping mattress capable of being disposed on a ground surface. Otherwise, the mattress may be in the form of a pad capable of being disposed upon chairs or the like and to fit to the contour of the chair or other item. Nevertheless, the mattress of the invention is referred to as a mattress, since it will in that sense become a body supporting member.
The mattress of the present invention comprises an inner foam core of the type which is capable of being rolled or folded. An outer flexible and foldable fabric cover surrounds and encloses the inner foam core. Moreover, air spaces exist in the foam core so that the mattress can be expanded when a valve on the mattress is opened and deflated when the mattress is compressed and the valve is opened.
The inner foam core is intimately bonded to the inner surface of the outer fabric cover and is thoroughly bonded to all portions of the recesses or grooves and raised portions during the bonding process, as hereinafter described. When the fabric cover is bonded to the foam core, they effectively become an integral or a single unit.
In a preferred embodiment of the invention, the outer fabric cover is bonded to the foam core usually through a thermoplastic layer. Thus, when the thermoplastic layer is melted during the bonding operation, it will cause an integral bond between the outer fabric cover and the foam core, and even in the region of the grooves and raised portions. It is recognized that when the fabric cover becomes bonded to the foam core, that bond effectively creates an integral construction in which the fabric permanently becomes bonded to the core. This is particularly true because of the fact that the thermoplastic resin literally creates an integral-type bond which is not readily broken.
In the present invention, the outer cover may be made of a suitable plastic as, for example, one of more forms of vinyl plastic. The foam core may also be formed of a plastic material, such as a urethane material. In addition, the foam core is preferably of an open cell construction which will allow the foam to receive air and to permit the escape of air.
At least one surface of the mattress, such as the upper surface, or at least a major portion of the surface area of the upper surface, is provided with a cratered body supporting surface pattern. In this case, the surface pattern comprises a plurality of spaced apart grooves formed in the cover and in the foam core and thereby defined raised portions or projections. In effect, and in a generic sense, the surface therefore becomes somewhat of a xe2x80x9cdimpledxe2x80x9d surface as, for example, with a so-called egg crate type surface pattern.
Thus, in the present invention, the term xe2x80x9ccrateredxe2x80x9d merely implies that there are projections and grooves in a major portion of the upper body supporting surface of the mattress. In effect, the upper surface is frequently referred to as a xe2x80x9ccrateredxe2x80x9d surface inasmuch as there are a series of regular depressions formed in a substantial portion of the upper body supporting surface of the mattress. These depressions exist in regular and pre-determined patterns and thereby form raised portions or projections having the same pre-determined pattern as, for example, a polygonal pattern. Thus, the term xe2x80x9ccrateredxe2x80x9d would also incorporate a so-called xe2x80x9cdimpledxe2x80x9d upper surface, that is, one with the so-called xe2x80x9cegg-crate shaped construction. In a macro-sense, the upper surface is linear in most of the embodiments in view of the fact that the upper surfaces of each of the projections are flat. Moreover, the upper surfaces of each of these projections lie in the same horizontal plane when the mattress is disposed in a horizontal position. Thus, and in the macro-sense, one laying on the mattress or otherwise being supported by the mattress would generally feel a flat or level upper surface, although because of the grooves and projections, the upper surface is actually not a flat or non-level upper surface.
In a preferred embodiment, the raised portions are formed by polygons and, thus, the grooves themselves form polygonal shapes. Thus, the surface pattern could be in the form of a hexagonal shape, an octagonal shape, or the like. However, it is also possible to use other surface patterns as, for example, a surface pattern formed by circles, squares or the like.
It is preferable, in accordance with the present invention, to provide a surface pattern in which the recesses or grooves are continuous in that they are connected to one another and extend ultimately to the edges of the mattress or at least the edges of the cratered body supporting surface configuration.
The mattress could have a relatively flat top surface, except for the dimpled surface construction thereon. In other words, no pillow is formed therein, and one portion of the mattress would not lie out of a plane of another major portion of the mattress. However, it is also possible to construct the mattress with an integral pillow. In this case, the non-level body supporting surface pattern construction would not necessarily extend to the pillow section, since the latter should have a relatively smooth surface to function as a pillow.
The walls of the raised portions in the mattress can be vertically arranged when the mattress is disposed on a horizontal surface. Otherwise, the walls may be at an incline, such that the upper surface of a pattern, such as a polygonal pattern, has a smaller size than the base of the raised sections or projections in that pattern. In this sense, the side walls of the raised portions incline inwardly and upwardly. Nevertheless, the upper surfaces of each of these raised such portions are flat and all of the upper surfaces lie generally in the same horizontal plane.
In an even more preferred embodiment of the invention, it is preferable to have the recesses at a depth of between about one-sixteenth of an inch to about one-half of an inch. In a more preferred embodiment, the depth will range from about one-eighth inch to about one-fourth inch.
The present invention fulfills the above and other objects and advantages in the provision of a mattress which has a non-level surface and in which the mattress effectively becomes a single unitary construction. The present invention also fulfills the above and other objects in the provision of a method which achieves this mattress construction. This mattress and the method are further exemplified by the following detailed description and the accompanying drawings. However, it is to be understood that this following detailed description and the accompanying drawings are only set forth for purposes of illustrating the general principles of the invention. Therefore, this following detailed description and accompanying drawings are not to be taken in a limiting sense.